A Combination of Rewriting and Constraint Solving for the Quantifier-Free Interpolation of Arrays with Integer Difference Constraints

The use of interpolants in model checking is progressively gaining importance. The application of encodings based on the theory of arrays, however, is limited by the impossibility of deriving quantifier-free interpolants in general. To overcome this problem, we have recently proposed a quantifier-free interpolation solver for a natural variant of the theory of arrays. However, arrays are usually combined with fragments of arithmetic over indexes in applications, especially those related to software verification. In this paper, we propose a quantifier-free interpolation solver for the variant of arrays considered in previous work when combined with integer difference logic over indexes.